(i) Field of the Invention
The present invention relates to an electric noise absorber which is attached around an electric wire of electronic apparatus to absorb electric noises generated inside the electronic apparatus or electric noises transmitted to the electronic apparatus from the outside via the electric wire.
(ii) Description of the Related Art
In a conventional art for removing or suppressing electric noises flowing through the electric wire, a magnetic body, for example, of ferrite is attached around the electric wire to attenuate the electric noises flowing through the wire. Examples of such known electric noise absorber include a non-divided type absorber in which an annular closed magnetic path is formed only by a magnetic body, a divided type absorber in which the closed magnetic path is formed when the electric wire is surrounded with a plurality of divided magnetic body parts, and the like. When an annular magnetic flux is generated by electric noises in the closed magnetic path formed by the magnetic body, the electromagnetic energy of the electric noise is converted to a heat energy inside the magnetic body. As a result, the electric noises are attenuated. When the electric wire is wound around the magnetic body in such a manner that the electric wire passes plural times inside the closed magnetic path formed by the magnetic body, i.e., a hollow in the magnetic body, the electric noises can more effectively be absorbed.
However, the number of windings of the electric wire passed through the hollow of the magnetic body is limited by the relationship between the thickness of the electric wire and the size or thickness of the hollow formed in the magnetic body. The electric noise absorbing performance cannot be enhanced further. The ability of preventing the operation error or failure of the electronic apparatus from being caused by the electric noises is also limited.